1. Field of the Invention
The present invention relates to a heater of the type comprising a housing having a heat transmitting wall, main end walls and main body walls, the heater element being mounted in the housing behind the heat transmitting wall and air inlet and outlet holes.
2. Background Information
Generally speaking these are mains powered heaters. One of the problems is they have a large number of inlets and outlets to allow them to keep the heating element cool. This makes them susceptible to water ingress. The housing can get extremely hot during use and can be a hazard if somebody touches it. They have been particularly useful for indoor heating such as, for example, in large arenas.
Such heaters are often called radiant heaters to distinguish them from heaters which work on the principle of heat convection. The heat rays are partially absorbed and partially reflected by the surfaces they impinge on and are thus very useful for instant, heat and for heating large areas with high air movement such as assembly halls, churches or the outdoors. The most useful form of such heater is one utilising a quartz element operating at temperatures in excess of 2000.degree. C. The present invention is particularly directed to such radiant heaters, simply referred to as heaters.
Mains powered electrical heaters are the preferred heating unit for many uses and particularly for indoor use, however, heretofore they have not been particularly successful for outdoor use because they have been unable to withstand adverse ambient conditions. Some of the major accidents occur outdoors when high voltage electrical units are used. For this reason, it is now almost essential on all building sites, for example, to have low voltage hand tools and the like. However, such low voltage units are not suitable generally for heating units. Thus, there is a need for a mains powered electrical heater which can use the full voltage of the mains such as 220 to 240 volts without the need for step down transformers and the like.
Such a mains powered electrical heater must be capable of withstanding not only ordinary adverse ambient conditions but also man induced adverse conditions. The principal problem is undoubtedly the ingress of moisture into such heaters. Obviously, this can be caused by nature such as by driving rain and the like, but equally can be caused by some form of human intervention such as the use directly of hose pipes and the like directed onto the heater, burst pipes and so on.
Further in many horticultural and agricultural use such as the rearing of animals, it is necessary to provide conditions of considerable humidity and at the same time provide heat. Often these, particularly with animal houses, have to be washed down regularly and personnel uses hoses and the like to wash down the buildings and inevitably accidents occur.